Refrigeration



July 12, I932 w. E. zl'EBER 1,866,992

REFRIGERATION Filed oct. 10.1'929 messed Julyla 1932 Y v'..UNrrEo STATES p PATENT ori-Ica WILLIAM E. ZIEBEB, 0F YORK, PENNSYLVANIA, ASSIGNOR- T0 YORK ICE IAGHINERY CORPORATION, YORK, PENNSYLVANIA, A GOBPORATION 0F DELAWARE nnrmemrron l Application led Uctober l0, v1929. Serial No. 398,745.

This invention relates to refrigeration and particularly vto the automatic control -of each one of a plurality of evaporators connected to the circuit, each evaporator being` controlled independently of the other. The invention further includes in combination with the above recited features, the ,use of means to control the entire system by starting and stopping thecompressor. .l

In a priorapplication Serial Number 299,271, led August 13th, 1928, there is described a method of and apparatus for controlling ooded evaporators by regulating the suction connection -so as to develop within the' evaporator a vapor pressure which at times displaces liquid refrigerant from the evaporator and thus controls its refrigerative effect:

The disclosure in said prior application is based ona system comprising a plurality of ice cream freezers, to and from which .volatile liquid refrigerant is admitted and discharged to control the freezing action. In ordinary operation of ice cream freezers thecontrol is to effect periodic suspension of the refrigerative action.

I have'determined, however, that the principle disclosed and broadly claimed in said prior application can be used to effect progressive regulation of the refrigerative action. Briefly, it is possible to throttle the suction connection and develop in the evap-` oration a variable vapor pressure which will resultinvthe partial'displacement of liquid refrigerant from the evaporator and a consequent reduction of the refrigerative eifect. AThe present application is limited to progressive regulation and is subordinate to the prior a phcation above identified.

Anot er feature of the presentin'vention is the use of an evaporator gravi .fed from a receptacle containing liquid re igerant and maintained at suction pressure, the evaporal tor having two connections withthe receptacle, one or both connections being below A suction trap or a combined suction and liquid A the liquid level in the receptacle. One 'connectionis constantly open andthe other is valve-controlled. The receptacle may be a line connected with such a trap. f" Two preferred embodiments of the invention are illustrated and described hereinafter, one of which is particularly adapted to installations where the evaporators are located on different floors of a building and consequently are at decidedly diiferent levels.

These preferred embodiments of the invention are illustrated in the accompanying drawing, in which,

Fig. l is a diagratic elevation of a refrigerative vcircuit showing four 'different types of eva orators connected to a single circuit and in s ependently controlled, ithere being also an pressor associated with one evaporator.

Fig. 2 is a similar view-showing a modication. In this modication the compressor automatic control' forY the comecontrol is omitted to simplify'the drawing,

but it may be used in the same form as that shown in Fig. 1.

In the drawing, 11 illustrates an ordinary I compressor which is driven by means of an denser 15 here illustrated as ofthe shell'and tube water-cooled type, ,although any preferred condenser may be` used. a Refrigerant liqueed in the condenser 15 drains from the bottom of the condenser to a iloat'trap 16. The trap 16 is provided with afloat 17 which 'upon rise of liquid level in the Vtrap casing opens the valve 1'8 to permit liquid refrigen ant to iow to a comblned'liquid and vapor j line 19. The line 19 is at least large enough to permit a partial separation of liquid and vapor, and to permit concurrent flow of the two streams of liquid and vapor' to a separating tra or drum 21. This drum 21 is'connected y.the suction line 22 with the suc `tion of the compressor 11. It follows that the liquid line `19. is maintained at suction .pressure with the result that a portion of the liquid refrigerant immediate y i vaporizes, cooling the remainder. The line 19 and tra 21 in effect form a single volume maintain at -suction pressure. While the line 19 iis shown as entering the top of the trap 21 this is not essential. v

In the arrangement illustrated, the line 19 tends to drain toward the trap 21, thus main taining the upper portion of the line free Q10 valves.

of liqu1d. The evaporators 23, 23a and 23b intercept and evaporate a considerable portion of the liquid, so that usually only a relatively small quantity Hows to trap 21.

The horizontal portion of the pipe line 19 and the trap 21 form what is, in effect, a sin` gle receptacle maintained at suction pressure. The float trap 17' operates continually while the compressor is in operation, to deliver high pressure li uid refrigerant into low-pressure line 19. n admission part of this boils away cooling the rest to the temperature corresponding to suction pressure.

-There is thus at least a trickle of cold liquid refrigerant flowing most of the time in the bottom of the horizontal run of pipe 19 toward trap 21.

As will be understood from details described hereinafter, this liquid ilow is at times supplemented by liquid refrigerant displaced from one or more evaporators by the regulatory action of their thermostatic At any rate there is, whenever the compressor is running, liquid refrigerant flowing in the horizontal run of pipe 19, so that a liquid level is established in this pipe. The upper portion of the pipe 19 serves as a vapor passage. v

Mounted below the line 19 so as to lill with liquid by gravity flow from the line 19 are the evaporators, three in number. For example, the coil 23 is an ordinary trombone coil. The connection 24 is preferably without any controlling valves and the connection 25 is provided with a hand operated stop valve 26 for the purpose of shutting down the evaporator coil permanently, and with the thermostatically operated valve 27 performing the-normal automatic regulation.' This valve is actuated by a thermostatic unit 28 preferably of the progressively acting type so arranged that when the temperature in the chamber 29,y within which the coil 23 isy mounted, rises the valve 27n will be radually opened, and as the temperature alls, the valve 27 will be gradually closed. The thermostatic element 28 thus acts to. preserve in the chamber 29 a temperature which is regulated within relatively close limits.

In another chamber or space 31, there is shown an evaporator coil 23, with two connections to the line. The connections and valves associated with this coil are similar to those associated with the coil 23 and are similarly numbered lwith the subscript a. Coil 23a is submerged in water in a tank 32 and functions to cool that water. In order to secure a proper regulation of the Water temperature the thermostatic element 28a is submerged in the water in the tank 32. f

In a third chamber '33 is a third coil 23h having connections and valves functionally `similar to those associated with the coil 23,

but differently arranged. The coil 23", forms the part of a brine cooler of the double pipe type, and the sinuous chamber 34 forms a passage for brine which surrounds the coil 23". In orderv to regulate the valve 27 b in response to the temperature of the olf-flowing brine, the thermostatic element 28b is indicated as closely associated with the lower end of the sinuous chamber 34 so as to respond to the brine temperature. There is also a slight change in the connections, the pipe 241 serving as a combined liquid and vapor line, that is an extension of line 19 to which the coil 23b has two connections, one (the lower) constantly open and the other controlled by valves 26b and 27". This arrangement is equivalent to and interchangeable with that previously described.

The evaporators might be multiplied almost indefinitely and might be of the same or different types. It is not essential that any evaporator be connected directly to the trap 21, but it is conveniently possible to connect an evaporator to this trap and to illustrate that possibility I show a .fourth evaporator 230 which is enclosed in a separate cold room or space 35. The connection 240 which is the liquid connection leads from the bottom of the trap 21, and the connection 250 leads, preferably, but not necessarily, to the top of the trap 21. The stop valve 260 and the regulating valve 270, with its thermostatic control element 280, are similar in form and functions to ythe similarly numbered parts asso-I ciated with the coil 23.

The trap 21 in the ordinary operation of the device will serve to accumulate a considerable quantity of liquid refrigerant, and for this reason it is desirable-that the coil 23o be the one which carries the heaviest and most sustained refrigerative load.

On this assumption, there is shown lin the ioo chamber 35 a thermostatic controller 36 which is connected by the wires 37 with an electrically actuated motor controlling switch 38. No 'y attempt has been made to illustrate in detail thethermostatic switch 36 or the motor controlling switch 38, but I contemplate using mechanism well known in the art and provided with those safety devices which are in currentuse. As the addition of these features involves nothing novel, and as the present inp trolled valve 27 c closes. The switch 36 is so Lacasse adjusted that when, or shortly after, the thermostatic valve 27o closes, the thermostatic switch 36 will function to stop the motor 12, and'will function to start the motor 12 at or about the time the valve 27 c opens` While itis convenient to treat the connections 24, 24a, etc. as the liquid connections, and the connections 25, 25a, etc'. as the lsuction connections to and from the various evaporators 23, 23a and 236, their functions'are not necessarily absolutely distinct, for under some conditions vapor will rise through the connections 24, 24a, etc. However, the flow through the evaporators isl generally' in the w direction implied by the designations given. ume, for example, that the thermostatic element 28 partially closes the valve 27. `The vapor pressure in the corresponding evaporator 23 will rise somewhat and a portion of the liquid refrigerant will be displacedthrough the pi 24 and will flow through the pipe 19, eit er to another eva orator or to the trap 21. Complete closure o the valve 27 will result in the displacement of all liquid 25 refrigerant from the coil 23. The subsequent opening of the valve 27 will result in the entrance of liquid refrigerant into the coil 23, the amount of'such refrigerantincreasing as the valve opens until the coil 23 is comao pletely filled, and the full refrigerative effect is resumed. Referring now to Figure 2, the compressor is indicated at 51 and the motor at'52 and the driving belt at 53. The compressed refrigerant leaves by the high pressure line 54 which delivers it to a condenser 55 in which y it is li ueed. .The liquefied refrigerant flows A from t e bottom of the condenser 55 ,to a float trap 56 connected top and bottom to a suc- -tion trap 61. The float 57 in the trap 56 controls theV valve 58 so as to preserve a constant level of liquid refrigerant inthe trap 61. I i The suction line 62 leads from the top of .the trap 61 to the suctionof the compressor. Leading from the bottom of the trap 61 is a downwardly extending liquid line 59. This is connected to the lower ends of three evaporator coils 63, 63a and 635. The upper end of each of these coils is connected to a, vapor line 60, but each4 such connection is controlled by a hand operated stop valve 66, 66a or 665 as the case may be, and byv an automatic control valve 67, 67a or 676. Each of the valves Vjust mentioned is controlled by a corresponding pro essive thermostat unit 68, 68a or 685. T e stop valves 66, 66a and 666., are used merely to shut down t e corresponding coil for an indefinite period. The valves 67, 67a etc. are progressively opened and closed by their corresponding thermostatic units 68 to control the vapor ressure inthe coil and thus to displace' the hquid refrigerant from the coil in varyi degrees. When .the coil is ful-l of liquidl emaxiinum rerigerative 'effect issecured..\ When it is.

tem a refrigerated displayl case) proportion of coil which is liquid l ed.

Itl is obvious that a thermostatic switch'.

similar to the thermostatic switch 36 may be mounted on any floor, preferably that having the 'severest and most sustained refrigerative load, and might be'arranged to startl and stop the motor 52 ina manner identical with. that described with reference to Fig. 1.

The use of a combined liquid and vapor line such as the line L9 of Fig. 1 is useful and is an important feature .of the present invention, particularly in conjunction with refrigerative evaporators having 'two Icon,- nections to that'line, the evaporators bein located below the line so as to lill with liqui by gravity flow therefrom.

The arrangement has peculiar advantages."

in defrosting. f If either the valve 26 or the valve 27 for example, completely closed the liquid refrigerant in the coil, such as coi 23, is completely expelled in a relatively short time,j As a result the coil spontaneous# ly defrosts itself. Such defrosting would not occur if the liquid refrigerant remained in the coil.

.The system is ofgreat practical utility where a number of eva orators must closely regulated each in e endently of the others.- One installation w ich has demon-k soy strated great utilityis that made in s lnall butcher shops wherethere is a relatively large butcher box or refrigerator, whose u nit is subjectedl to a relatively light refrigerative load, and where there is ,also in the'san'ie sye# which, jected to a cause of frequent opemng, is'su heavy and sustained refrigerative load. In.

such cases the evaporator unit inthe butcher box is equipped withy a control valve such` as thevalve 26 or 27, it being referred to use an automatic 'valve such as t e valve 27;

Such a unit may cry/,may not be used in the..

display case, although its use is preferred,

but in any event the thermostatic control 36 is put in the display case, thus ensuring re- Q frigeration to that case at all times-when its temperature tends to rise above the desired:

value. The automatic valve controlling the A butcher box coil will ensurethe maintenance ofthe'proper temperature in the butcher box.

. Various other'practical modifications involving siinilarv rmciples will readily suggest themselves, an need not be discussed in detail. The useof` a. progressive thermostatic actuator in conjunction with a progressive valve suchl as the valve 27 olfersa peculiar-r ly even an'd gradual regulation such as has long been desired and seldom obtained in the art.

, It isapparently to illustrate` and describe vin the .theririostatfl valves, of which the valve mechanism 27, 28, is typical, as these may assume various forms and are standard articles of commerce. O ne such known type of thermostatic valve 1ncludes a valve urged closed by a spring and urged open in opposition to the action of said spring by vapor pressure acting against a metallic bellows diaphragm. The vapor pressure is that generated by evaporationof a volatile liquid which develops the opening pressure at or about the temperature which it is desired to maintain. In refrigeration work it is common to use for this purpose one of the volatile refrigerants However, the form4 of the thermostaticI valve is immaterial.

The particular modifications shown in the drawing are intended to be illustrative rather than limiting, and it is understood that the invention is capable of embodiment in many different forms.

What isclaimed is,-

1. The method of controlling the refrigerative action of a normally flooded evaporator, having two independent connections with a trap in which a charge of liquid refrigerant is maintained under suction pressure, and from which the evaporator is fed with liquid refrigerant by gravity flow, which consists in variably throttling one of said connections according to changes in the artificial temperature created by said evaporator, while evap oration' of refrigerant is taking place in the evaporator, and thus varying the effective surface of the evaporator by a varying partial displacement of liquid refrigerant therefrom.

2. In a refrigerating system, the combination of a receptacle maintained. at suction pressure and partially filled with volatile liquid refrigerant; and an evaporator arranged to fill with liquid refrigerant by gravity flow from said receptacle and having two connections therewith both below the liquid level in the receptacle.

3. In a refrigerating system, the combination of a receptacle maintained at suction pressure and partially filled with volatile liquid refrigerant; an evaporator arranged to fill with liquid refrigerant by gravity flowv from said receptacle and having two connections therewith both below the liquid level in the receptacle; and a valve controlling one of said connections.

Ll. In a refrigerating system, the combination of a receptacle maintained at suction pressure and partiallyv filled with volatile liquid refrigerant; an evaporator arranged to fill with liquid refrigerant by'gravity flow from said receptacle and having two connections therewith both below the liquid level in the receptacle, and one of said connections being constantly open; and a valve controlling the other connection.

5. In a refrigerating system, the combination of a receptacle maintained at suction pressure and partially filled with volatile liquid refrigerant; an evaporator arranged to fill with liquid 'refrigerant by gravity flowl tion of a receptacle maintained at suction pressure and partially filled'with volatile liquid refrigerant; an evaporator arranged to fill with liquid refrigerant by gravity flow from said receptacle and having two connections therewith both below the liquid level in the receptacle, one of said connections being constantly open; a valve controlling the other connection; and a thermostatic actuator connectedto open and close said -valve progressively as the artificial temperature created by said evaporator rises and falls.

7 .f In a refrigerating system, the combination of a receptacle maintained at suction pressure and partially filled with volatile liquid refrigerant; an evaporator arranged to lillwith liquid refrigerant by gravity flow from said receptacle and having two connections therewith, atleast one of whichis below the liquid level in the receptacle; a valve controllingthe other connection; and thermostatic means for opening and `closing said valve in response to the rise and fall of the artificial temperature created by said evap orator.

8. In a refrigerating system, the combination of a receptacle maintained at suction pressure and partially filled with volatile liquid refrigerant; an evaporator arranged to fill with liquid refrigerant by gravity flow from said receptacle and having two connections therewith, atleast one of which is below the liquid level in. the receptacle; aA valve controlling' the other connection; and thermostatic means for progressively opening and closing said valve in response to the rise and fall of the artificial temperature created by said evaporator.

`9. In a multiple refrigerating system, the combination of a receptacle maintained at suction 'pressure and partially filled with volatile liquid refrigerant; and a plurality of independent cooling units each including an evaporator arranged to fill with liquid refrigerant by gravity flow from' said receptacle, and having 4two connections therewith, at least one of such connections being below the liquid level in the receptacle, a valve controlling the other connection and thermo,

static means for opening and closing said valve in response to the-rise and fall of the artificial temperature created by the associated evaporator.

10. In a multiple refrigerating system, the combination of a receptacle maintained at suction pressure and partially filled with volatile liquid refrigerant; and a plurality 5 of independent cooling units each including an evaporator arranged to fill with liquid refrigerant by gravity flow from said receptacle, and having two connections therewith, at least one of such connections being below l the liquid level in the receptacle, a valve controlling the other connection and thermostatic means for progressively opening and closing said valve in response to the rise and fall of the artificial temperature created by l the associated evaporator.

11. A multiple refrigerating system comprising in combination a suction trap; a compressor whose suction is connected therewith; lmeans for driving said compressor; a condenser to which the compressor delivers; and means controlling the delivery of liquid refrigerant from the condenser to said trap, whereby a refrigerant circuit is formed; a plurality of cooling units connected with said circuit at least one of which includes an evaporator arranged to fill with liquid refrigerant by gravity flow from said trap, and having two connections therewith, at least one such connection being below the 50 liquid level in the trap, a valve controlling the other connection, and thermostatic means for opening and closing said valve in response to the riseand fall of the artificial temperature created by said evaporator; and

35 thermostatic means responsive to the artificial temperature created by one of said cooling units for starting and stopping said compressor driving means.

12. A multiple refrigerating system comprising in combination, a suction trap; a

compressor whose suction is connected therewith; means for driving said compressor; a condenser to which the compressor delivers; and means controlling the delivery of liquid refrigerant from the condenser to said trap, whereby a refrigerant circuit is formed; a plurality of.cooling units connected with said circuit, at least one of which includes an evaporator arranged to fill with liquid refrig- 0 erant'by gravity flow from said trap, and

' having two connections therewith, at least one such connection being below the liquid level in the trap, a valve controlling the other connection, and thermostatic means for progressivelyopening and closing said valve in response to the rise and fall of the artificial temperature created by said evaporator; and thermostatic means responsive to the `arti ficial temperature created by one of saidicool- 50 ing units for starting and stopping said conipressor driving means.

13. In a refrigerating system, the combination of a condenser; a combined gas and liquid refrigerant line arranged tobe fed with liquid from said condenser; means controlling the feed of liquid from the condenser to said line; a trap for intercepting liquid refrigerant, with the gas space of which said line communicates and toward which it drains; means for withdrawing gas from said trap and delivering it under higher pressure to the condenser; and at least one evaporator connected with said combined line and arranged to fill with liquid refrigerant by gravity flow therefrom.

14. In a refrigerating system, the combination of a condenser; a combined gas and liquid refrigerant line arranged to be fed with liquid from said condenser; means controlling the feed of liquid from the condenser to said line; a trap for intercepting liquid refrigerant; with the gas space of which said line communicates and toward which it drains; means for withdrawing gas from said trap and delivering it under higher pressure to the condenser; an evaporator having two connections with said combined line and arranged to ill with liquid refrigerant by gravity flow therefrom; and valve means for controlling one of said connections.

15. In a refrigerating system, the combination of a condenser; a combined gas and liquid refrigerant line arranged to be fed with liquid from said condenser; meanscontrolling the feed of liquid from the condenser to said'line; a trap -for intercepting liquid refrigerant, with the gas space of which said line communicates and toward which it drains; means for withdrawing gas from said trap and delivering it under higher pressure to the condenser; a'n evaporator having two connections with said combined line and arranged to ill with liquid refrigerant by gravity-flow therefrom; valve means for controlling one of saidy connections; and thermostatic means for controlling said valve means.

16. In a refrigerating system, the combination of a condenser; a combined gas and liquid refrigerant line arranged to be fed with liquid from said condenser; means controlling the feed of liquid from the condenser to said line; a trap for intercepting liquid refrigerant,'with the gas space of which said line communicates and toward which .it drains; means for withdrawing gas from said trap and delivering it under higher pressure to the condenser; an evaporator having two connections with said combined line and arranged to fill with liquid refrigerant by gravity flow therefrom; valve'means for controlling one 'of said connections; and proloo gressively acting thermostatic means for controlling said valve means.

In testimony whereof I have signed my name 'to this specification.

WILLIAM E. ZIEBER. 

